# Expressions
You can add expressions strings to perform functions in Amazon Lex V2. This table shows the syntax and examples that can be used in SRGS expressions.
| Expression type | Syntax | Example | Supported? |
| --- | --- | --- | --- |
| Regular expression literal | String literal containing valid [regex special characters](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions) | "^\d\.$"
| No |
| Function | function functionName(parameters) \$1 functionBody\$1 | var x = function calc() {
return 10;
} | No |
| Delete | delete expression | delete obj.property;
| No |
| Void | void expression | void (2 == '2');
| No |
| Typeof | typeof expression | typeof 42;
| No |
| Member index | expression [ expressions ] | var fruits = ["apple"];
fruits[0];
| Yes |
| Member dot | expression . identifier | out.value
| yes |
| Arguments | expression (arguments) | new Date('1994-10-11') | Yes |
| Post increment | expression\$1\$1 | var x=10; x++;
| Yes |
| Post decrement | expression-- | var x=10; x--;
| Yes |
| Pre increment | \$1\$1expression | var x=10; ++x;
| Yes |
| Pre decrement | --expression | var x=10; --x;
| Yes |
| Unary plus / Unary minus | \$1expression / -expression | +x / -x;
| Yes |
| Bit not | \$1 expression | const a = 5;
console.log( ~a );
| Yes |
| Logical not | \$1 expression | !(a > 0 || b > 0)
| Yes |
| Multiplicative | expression ('\$1' \$1 '/' \$1 '%') expression | (x + y) * (a / b)
| Yes |
| Additive | expression ('\$1' \$1 '-') expression | (a + b) - (a - (a + b))
| Yes |
| Bit shift | expression ('<<' \$1 '>>' \$1 '>>>') expression | (a >> b) >>> c
| Yes |
| Relative | expression ('<' \$1 '>' \$1 '<=' \$1 '>=') expression | if (a > b) { ... } | Yes |
| In | expression in expression | fruits[0] in otherFruits;
| Yes |
| Equality | expression ('==' \$1 '\$1=' \$1 '===' \$1 '\$1===') expression | if (a == b) { ... } | Yes |
| Bit and / xor / or | expression ('&' \$1 '^' \$1 '\$1') expression | a & b / a ^ b / a | b
| Yes |
| Logical and / or | expression ('&&' \$1 '\$1\$1') expression | if (a && (b ||c)) { ...} | Yes |
| Ternary | expression ? expression : expression | a > b ? obj.prop : 0
| Yes |
| Assignment | expression = expression | out.value = "string";
| Yes |
| Assignment operator | expression ('\$1=' \$1 '/=' \$1 '\$1=' \$1 '-=' \$1 '%=') expression | a *= 10;
| Yes |
| Assignment bitwise operator | expression ('<<=' \$1 '>>=' \$1 '>>>=' \$1 '&=' \$1 '^=' \$1 '\$1=') expression | a <<= 10;
| Yes |
| Identifier | identifierSequence where identifierSequence is a sequence of [valid characters](https://developer.mozilla.org/en-US/docs/Glossary/Identifier) | fruits=[10, 20, 30];
| Yes |
| Null literal | null | x = null;
| Yes |
| Boolean literal | true \$1 false | x = true;
| Yes |
| String literal | 'string' / "string" | a = 'hello',
b = "world";
| Yes |
| Decimal literal | integer [.] digits [exponent] | 111.11 e+12
| Yes |
| Hex literal | 0 (x \$1 X)[0-9a-fA-F] | 0x123ABC
| Yes |
| Octal literal | O [0-7] | "O51"
| Yes |
| Array literal | [ expression, ... ] | v = [a, b, c];
| Yes |
| Object literal | \$1property: value, ...\$1 | out = {value: 1, flag: false}; | Yes |
| Parenthesized | ( expressions ) | x + (x + y)
| Yes |